Effects of excessive equatorial cold tongue bias on the projections of tropical Pacific climate change. Part I: the warming pattern in CMIP5 multi-model ensemble

2016 ◽  
Vol 47 (12) ◽  
pp. 3817-3831 ◽  
Author(s):  
Gen Li ◽  
Shang-Ping Xie ◽  
Yan Du ◽  
Yiyong Luo
Keyword(s):  
Climate Change ◽  
Tropical Pacific ◽  
Cold Tongue ◽  
Model Ensemble ◽  
Warming Pattern

scholarly journals Global Model selection for evaluation of Climate Change projections in the Eastern Tropical Pacific Seascape

2017 ◽  
pp. 67-81
Author(s):  
Hugo G. Hidalgo ◽  
Eric J. Alfaro
Keyword(s):  
Climate Change ◽  
Model Selection ◽  
20Th Century ◽  
General Circulation ◽  
Tropical Pacific ◽  
Global Model ◽  
Model Ensemble ◽  
Eastern Tropical Pacific ◽  
Climate Change Projections ◽  
Selection For

Two methods for selecting a subset of simulations and/or general circulation models (GCMs) from a set of 30 available simulations are compared: 1) Selecting the models based on their performance on reproducing 20th century climate, and 2) random sampling. In the first case, it was found that the performance methodology is very sensitive to the type and number of metrics used to rank the models and therefore the results are not robust to these conditions. In general, including more models in a multi-model ensemble according to their rank (of skill in reproducing 20th century climate) results in an increase in the multi-model skill up to a certain point and then the inclusion of more models degrades the skill of the multi-model ensemble. In a similar fashion when the models are introduced in the ensemble at random, there is a point where the inclusion of more models does not change significantly the skill of the multi-model ensemble. For precipitation the subset of models that produces the maximum skill in reproducing 20th century climate also showed some skill in reproducing the climate change projections of the multi-model ensemble of all simulations. For temperature, more models/simulations are needed to be included in the ensemble (at the expense of a decrease in the skill of reproducing the climate of the 20th century for the selection based on their ranks). For precipitation and temperature the use of 7 simulations out of 30 resulted in the maximum skill for both approaches to introduce the models. Citation: Hidalgo, H. & E.J. Alfaro. 2012. Global Model selection for evaluation of climate change projections in the Eastern Tropical Pacific Seascape. Rev. Biol. Trop. 60 (Suppl. 3): 67-81. Epub 2012 Dec 01.

scholarly journals Eastern equatorial Pacific warming delayed by aerosols and thermostat response to CO2

2021 ◽  
Author(s):  
Ulla K. Heede ◽  
Alexey V. Fedorov
Keyword(s):  
Climate Change ◽  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Future Projections ◽  
Aerosol Forcing ◽  
Eastern Equatorial Pacific ◽  
Warming Pattern ◽  
Future Warming ◽  
East West ◽  
The Tropical Pacific

<p>Understanding the tropical Pacific response to global warming remains a challenging problem due to discrepancies between models and observations, as well as a large intermodel spread in future projections. Here, we assess the recent and future evolution of the equatorial Pacific east-west temperature gradient, and the Walker circulation within the CMIP6 dataset. Using 40 models, we compare simulated tropical climate change across a wide range of experiments with varying CO<sub>2</sub> and aerosol forcing. In abrupt CO<sub>2</sub>-increase scenarios, many models generate an initial strengthening of the east-west gradient resembling an ocean thermostat (OT), characterized by lack of warming in the central Pacific, followed by a small weakening; other models generate an immediate weakening that becomes progressively larger establishing a pronounced eastern equatorial Pacific (EP) warming pattern. The initial response in these CO<sub>2</sub>-only experiments is a very good predictor for the future EP pattern simulated in future warming scenarios, but not in historical simulations showing no multi-model trend. The likely explanation is that recent CO<sub>2</sub>-driven changes in the tropical Pacific, which are relatively small compared to future projections, are masked by aerosol effects. In future warming scenarios, however, the EP warming pattern emerges within 20-40 years as greenhouse gases overcome aerosol forcing. These findings highlight the need to understand the largely overlooked, but possibly significant role of aerosols in delaying sea surface warming in the tropical Pacific, and the implications for predicting future climate change across the tropics.</p>

scholarly journals Comparison of regional characteristics of land precipitation climatology projected by an MRI-AGCM multi-cumulus scheme and multi-SST ensemble with CMIP5 multi-model ensemble projections

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Rui Ito ◽  
Tosiyuki Nakaegawa ◽  
Izuru Takayabu
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
General Circulation ◽  
Annual Precipitation ◽  
Cmip5 Models ◽  
Climate Projections ◽  
The Tibetan Plateau ◽  
Model Ensemble ◽  
Uncertainty Range ◽  
High Performing

AbstractEnsembles of climate change projections created by general circulation models (GCMs) with high resolution are increasingly needed to develop adaptation strategies for regional climate change. The Meteorological Research Institute atmospheric GCM version 3.2 (MRI-AGCM3.2), which is listed in the Coupled Model Intercomparison Project phase 5 (CMIP5), has been typically run with resolutions of 60 km and 20 km. Ensembles of MRI-AGCM3.2 consist of members with multiple cumulus convection schemes and different patterns of future sea surface temperature, and are utilized together with their downscaled data; however, the limited size of the high-resolution ensemble may lead to undesirable biases and uncertainty in future climate projections that will limit its appropriateness and effectiveness for studies on climate change and impact assessments. In this study, to develop a comprehensive understanding of the regional precipitation simulated with MRI-AGCM3.2, we investigate how well MRI-AGCM3.2 simulates the present-day regional precipitation around the globe and compare the uncertainty in future precipitation changes and the change projection itself between MRI-AGCM3.2 and the CMIP5 multiple atmosphere–ocean coupled GCM (AOGCM) ensemble. MRI-AGCM3.2 reduces the bias of the regional mean precipitation obtained with the high-performing CMIP5 models, with a reduction of approximately 20% in the bias over the Tibetan Plateau through East Asia and Australia. When 26 global land regions are considered, MRI-AGCM3.2 simulates the spatial pattern and the regional mean realistically in more regions than the individual CMIP5 models. As for the future projections, in 20 of the 26 regions, the sign of annual precipitation change is identical between the 50th percentiles of the MRI-AGCM3.2 ensemble and the CMIP5 multi-model ensemble. In the other six regions around the tropical South Pacific, the differences in modeling with and without atmosphere–ocean coupling may affect the projections. The uncertainty in future changes in annual precipitation from MRI-AGCM3.2 partially overlaps the maximum–minimum uncertainty range from the full ensemble of the CMIP5 models in all regions. Moreover, on average over individual regions, the projections from MRI-AGCM3.2 spread over roughly 0.8 of the uncertainty range from the high-performing CMIP5 models compared to 0.4 of the range of the full ensemble.

scholarly journals Sea-surface temperature records of Termination 1 in the Gulf of California: Challenges for seasonal and interannual analogues of tropical Pacific climate change

2012 ◽  
Vol 27 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
Erin L. McClymont ◽  
Raja S. Ganeshram ◽  
Laetitia E. Pichevin ◽  
Helen M. Talbot ◽  
Bart E. van Dongen ◽  
...  
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Gulf Of California ◽  
Tropical Pacific ◽  
Sea Surface ◽  
Temperature Records

Communicating water-related climate change hazards to local stakeholders

2021 ◽  
Author(s):  
Laura Müller ◽  
Petra Döll
Keyword(s):  
Climate Change ◽  
Water Management ◽  
Climate Change Impact ◽  
Biosphere Reserve ◽  
Hydrological Models ◽  
Model Ensemble ◽  
Hydrological Hazards ◽  
Local Stakeholders ◽  
Change Impact ◽  
The Impact

<p>Due to climate change, the water cycle is changing which requires to adapt water management in many regions. The transdisciplinary project KlimaRhön aims at assessing water-related risks and developing adaptation measures in water management in the UNESCO Biosphere Reserve Rhön in Central Germany. One of the challenges is to inform local stakeholders about hydrological hazards in in the biosphere reserve, which has an area of only 2433 km² and for which no regional hydrological simulations are available. To overcome the lack of local simulations of the impact of climate change on water resources, existing simulations by a number of global hydrological models (GHMs) were evaluated for the study area. While the coarse model resolution of 0.5°x0.5° (55 km x 55 km at the equator) is certainly problematic for the small study area, the advantage is that both the uncertainty of climate simulations and hydrological models can be taken into account to provide a best estimate of future hazards and their (large) uncertainties. This is different from most local hydrological climate change impact assessments, where only one hydrological model is used, which leads to an underestimation of future uncertainty as different hydrological models translate climatic changes differently into hydrological changes and, for example, mostly do not take into account the effect of changing atmospheric CO<sub>2</sub> on evapotranspiration and thus runoff.   </p><p>The global climate change impact simulations were performed in a consistent manner by various international modeling groups following a protocol developed by ISIMIP (ISIMIP 2b, www.isimip.org); the simulation results are freely available for download. We processed, analyzed and visualized the results of the multi-model ensemble, which consists of eight GHMs driven by the bias-adjusted output of four general circulation models. The ensemble of potential changes of total runoff and groundwater recharge were calculated for two 30-year future periods relative to a reference period, analyzing annual and seasonal means as well as interannual variability. Moreover, the two representative concentration pathways RCP 2.6 and 8.5 were chosen to inform stakeholders about two possible courses of anthropogenic emissions.</p><p>To communicate the results to local stakeholders effectively, the way to present modeling results and their uncertainty is crucial. The visualization and textual/oral presentation should not be overwhelming but comprehensive, comprehensible and engaging. It should help the stakeholder to understand the likelihood of particular hazards that can be derived from multi-model ensemble projections. In this contribution, we present the communication approach we applied during a stakeholder workshop as well as its evaluation by the stakeholders.</p>

Effect of excessive equatorial Pacific cold tongue bias on the El Niño-Northwest Pacific summer monsoon relationship in CMIP5 multi-model ensemble

2018 ◽  
Vol 52 (9-10) ◽  
pp. 6195-6212 ◽  
Author(s):  
Gen Li ◽  
Yuntao Jian ◽  
Song Yang ◽  
Yan Du ◽  
Ziqian Wang ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
El Niño ◽  
El Nino ◽  
Equatorial Pacific ◽  
Northwest Pacific ◽  
Cold Tongue ◽  
Model Ensemble
Sign in / Sign up

Export Citation Format

Share Document